. >> woodruff: tensions in the east china sea hovered over vice president joe biden's visit to beijing today. u.s. officials say he and chinese president xi jinping traded arguments over china's new air defense zone around islands that japan also claims. later, in a subdued session with reporters, neither man mentioned the issue. instead, xi emphasized that diplomacy is needed from both the u.s. and china to maintain regional peace. >> ( translated ): both the international situation and the regional landscape are undergoing profound and complex changes. regional hotspot issues keep popping up, and china and the united states shoulder important responsibilities for upholding world peace and stability and promoting human development and progress. >> woodruff: the state-run english newspaper "china daily" was far less diplomatic. in a bluntly worded editorial, it accused the u.s. of casting a blind eye to japanese provocations. the editorial went on to say: "despite trying to present the image of being an impartial mediator, washington has obviously taken japan's side." the european comm